This invention relates to a synthetic plastic closure cap for bottles, consisting of a cylindrical part and a top plate connected in one piece therewith, the upper side of which top plate is intended for marking with an imprint.
Such synthetic plastic closure caps are predominating more and more over metal closures by reason of the most various advantages. However in practical use the inscription or marking of the top plates of the closures causes problems in as much as the synthetic plastic closure caps on the one hand can most expediently be printed on the top plate, but the top plate is subjected to mechanical abrasion when bottles or filled bottle carriers are place one upon the other, in such a way that the marking becomes unsightly and illegible. This affects synthetic plastic closure caps quite specially, because the imprint on the conventional synthetic plastic materials can be damaged relatively easily.
In known container lids with external bead, the danger of damage is already unintentionally reduced. Such protective edges are sometimes even provided only for aesthetic reasons, as illustrated for example in U.S. Pat. No. 3,766,882. The forming of such an edge on the container lid has however the consequence that printing becomes extremely difficult and complicated. Moreover a large part of the lid area available for printing is lost. Especially if for example as a result of legal regulations a multiplicity of information must be imprinted on the lid, it is necessary to have the largest possible area available for the provision of the marking, since otherwise the inscriptions would have to be reduced to an illegibly small scale. This applies quite especially to closure caps for bottles with small diameter.
Accordingly the invention is directed to the problem of providing a closure cap of the stated kind which can be provided in an optimally simple manner with an imprint which is not damaged either in storage or in transport of the individual closures, nor can be scraped away or otherwise mechanically scratched in the stacking of filled bottles or bottle carriers one upon the other.